Hatchet pick



Sept. 30. 19240 smzaz W. C. DAVIS HATCHET PI CK Filed Jan. 11. 1923 imme/14 4201 Patented Sept. 30, 1924.

attains HUB.

WALLACE CLYDE DAVIS, OF LINCOLN, NEBRASKA, ASSIGNOR TO THE L. D. CAULK COMPANY, OF MILFORD, DELAWARE, A CORPORATION OF DELAWARE.

HATCHET PICK.

Application filed January 11,1923.

To all whom it may concern:

Be it known that I, IVALLAGE CLYDE DAVIS, a citizen of the United States, residing at Lincoln, in the county of Lancaster and State of Nebraska, have invented cer tain new and useful Improvements in Hatchet Picks, of which the following is a specification.

This invention relates to surgical instruments and proposes the construction of a dental tool or pick the principal function of which is the cleaning out or enlarging of root canals by a chopping, as well as a picking or prying action.

One of the objects of the invention is the construction of a dental pick, the tool end of which is formed with a hatchet blade having the edge thereof lying in the plane of the axis of said pick. 7

Another object of the invention is the provision of a hatchet pick having the handle or shank of uniform cross sectional area between the manipulable portion thereof and the blade of the instrument.

Additional objects of the invention will appear in the following specification in which the preferred form of my invention is disclosed.

In the drawing similar reference characters refer to similar parts in all the views in which Figure 1 is a side elevation of a hatchet pick somewhat magnified.

Figures 2 and 3 are elevatio-nal views on a much enlarged scale of the ends of the hatchet pick, taken at right angles to one another, intermediate portions being broken away.

Figure 4 is a plan view of the hatchet pick shown in Figure 2.

Referring now in detail to the several figures, the numeral 1 represents a wire or rod which may be round or of any other desired shape and constituting the shank or handle of the hatchet pick. Up to the time of the present invention picks have been devised which comprise a shank similar to the wire 1 the inner end, or tool end of which is tapered from all sides to a point. Such an instrument is introduced in the root canal of a tooth'for cleaning out debris or enlarging the root canal by picking or prying obstructive particles-from the walls thereof. The pointed shape of the end of the usual pick is such as to cause it to Serial No. 612,057.

glance off from. an obstruction which it does not engage squarely with its point or at a suitable angle, causing the expenditure of many futile strokes in the cleaning out or enlarging operation, rendering the instrument inefficient in the most skilled hands.

The hatchet pick of the present invention substitutes for the pointed end of the ordinary pick a hatchet blade 2 which is preferably formed by beveling the opposite sides of the wire or shank l, forming an edge 3 instead of a point at the lower or operative end of the pick. Not only is the edge more reliably engageable with an obstruction than a mere point, but the pick may be reciprocated axially within the root canal by appropriate manipulative movement of the handle, imparting an inertia blow or impact against the obstruction within the root canal breaking it down by an actual chopping force rather than by a mere picking or prying movement which latter is the most that is possible with the old style pick. In order that the blow imparted to the handle of the hatchet pick by the operator may be transmitted without vibratory diminution to the point of application of the edge 3 within the root canal the shank or handle of the hatchet pick is made of unconstricted cross sectional area from the point at which the fingers of the operator are applied down "to the hatchet blade. I anr fully aware that cuttin instruments for different purposes have been devised in which a chisel blade is joined to the manipulative portion of the tool by a narrow neck, but such a construction would be inimical to the e'l'licient operation of the hatchet pick as the attempt to transmit an inertia force through a narrowed portion of the handle or shank results in dissipation of said force in lateral vibration of the narrowed portion, thereb lessening the impact blow of the hatchet blade against the obstructive matter in the root canal.

lVhile I have exemplified in the drawings and in the above description the preferred embodiment of my invention, as a hatchet pick having the edge thereof perpendicular to the axis of the shank and lying in the plane of said axis, it is quite obvious that the spirit of the invention would not be transcended by making the edge 3 oblique or by arranging it in a plane parallel to the axis of said hatchet pick, the essential principle of the invention being that the shank of the hatchet pick be of uniform cross sectional area from the point at which it is adapted to be grasped by the fingers of the operator down to the hatchet blade and that the edge of the latter terminate within the projected cross sectional area of the shank.

Having described my invention What I claim as new and desire to secure by Letters Patent is 2- '1. A hatchet pick for operating in root canals comprising a rectilinear shank having achopping blade at one end, said shank being of unconstrioted cross sectional area from the point of manipulation to said 15 chopping blade. 7

2. A hatchet pick for operating in root canals comprising a rectilinear shank of uniform cross sectional area and provided with a chopping edge at one end lying with- 20 WALLACE CLYDE DAVIS. V 

